At work I plug a Microsoft ergonomic keyboard into my PowerBook (and an IBM three-button-and-scroll-wheel mouse, and a ViewSonic LCD display). The Microsoft keyboard has the Option and Command keys backwards from what my hands know from many years of conditioning on Apple keyboards.
For the sake of this post, there is nothing in the world more annoying than switching my control keys. In fact, I have whined about conflicting keystrokes before. uControl to the rescue -- it lets you remap keys to where they belong.
Unfortunately, the update to Mac OS X 10.3.8 last week introduced the first breakage I've ever suffered from an OS X upgrade -- it broke compatibility with uControl. BAD BAD BAD. I immediately checked for an update to uControl -- no joy. So I Googled for an alternative and found DoubleCommand.
DoubleCommand has the virtue of working with 10.3.8 which was critical for me last week. I might even slightly prefer its interface. But uControl can apply its key mapping differently to different keyboards. So when I'm plugged into the Microsoft keyboard at work, it swaps the Option and Command keys, but if I type at the PowerBook keyboard, the Option and Command keys stay where they're supposed to be. By contrast DoubleCommand has only one map which applies to both keyboards. So either the map is correct for the Microsoft keyboard or for the PowerBook keyboard but not both. I've had to toggle the keyboard map twice-a-day. DoubleCommand's interface is simple enough to make this just three clicks in the control panel, but twice-a-day is a pain.
Happily, I checked uControl again tonight to find an update released for 10.3.8. HOORAY! I'm back to uControl!